Index: sbin/ipfw/ipfw.8
===================================================================
--- sbin/ipfw/ipfw.8
+++ sbin/ipfw/ipfw.8
@@ -1,7 +1,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 13, 2018
+.Dd November 27, 2018
 .Dt IPFW 8
 .Os
 .Sh NAME
@@ -2119,7 +2119,7 @@
 .Bl -tag -width indent
 .It Ar create-options : Ar create-option | create-options
 .It Ar create-option : Cm type Ar table-type | Cm valtype Ar value-mask | Cm algo Ar algo-desc |
-.Cm limit Ar number | Cm locked
+.Cm limit Ar number | Cm locked | Cm missing | Cm or-flush
 .It Cm type
 Table key type.
 .It Cm valtype
@@ -2130,6 +2130,12 @@
 Maximum number of items that may be inserted into table.
 .It Cm locked
 Restrict any table modifications.
+.It Cm missing
+Don't fail if table already exists and has exactly same options as new one.
+.It Cm or-flush
+Flush existing table with same name instead of returning error. Implies
+.Cm missing
+so existing tabel must be compatible with new one.
 .El
 .Pp
 Some of these options may be modified later via
Index: sbin/ipfw/ipfw2.h
===================================================================
--- sbin/ipfw/ipfw2.h
+++ sbin/ipfw/ipfw2.h
@@ -264,6 +264,9 @@
 	TOK_UNLOCK,
 	TOK_VLIST,
 	TOK_OLIST,
+	TOK_MISSING,
+	TOK_ORFLUSH,
+	TOK_OPTIONAL,
 
 	/* NAT64 tokens */
 	TOK_NAT64STL,
Index: sbin/ipfw/tables.c
===================================================================
--- sbin/ipfw/tables.c
+++ sbin/ipfw/tables.c
@@ -326,6 +326,8 @@
       { "algo",		TOK_ALGO },
       { "limit",	TOK_LIMIT },
       { "locked",	TOK_LOCK },
+      { "missing",	TOK_MISSING },
+      { "or-flush",	TOK_ORFLUSH },
       { NULL, 0 }
 };
 
@@ -388,16 +390,18 @@
  * Creates new table
  *
  * ipfw table NAME create [ type { addr | iface | number | flow } ]
- *     [ algo algoname ]
+ *     [ algo algoname ] [missing] [or-flush]
  */
 static void
 table_create(ipfw_obj_header *oh, int ac, char *av[])
 {
-	ipfw_xtable_info xi;
+	ipfw_xtable_info xi, xie;
 	int error, tcmd, val;
 	uint32_t fset, fclear;
 	char *e, *p;
 	char tbuf[128];
+	int missing = 0;
+	int flush = 0;
 
 	memset(&xi, 0, sizeof(xi));
 
@@ -456,6 +460,13 @@
 		case TOK_LOCK:
 			xi.flags |= IPFW_TGFLAGS_LOCKED;
 			break;
+		case TOK_MISSING:
+			missing = 1;
+			break;
+		case TOK_ORFLUSH:
+			missing = 1;
+			flush = 1;
+			break;
 		}
 	}
 
@@ -465,8 +476,30 @@
 	if (xi.vmask == 0)
 		xi.vmask = IPFW_VTYPE_LEGACY;
 
-	if ((error = table_do_create(oh, &xi)) != 0)
+	error = table_do_create(oh, &xi);
+
+	if (error == 0)
+		return;
+
+	if (errno != EEXIST || !missing)
 		err(EX_OSERR, "Table creation failed");
+
+	/* Check that existing table as same we try to create */
+	if (table_get_info(oh, &xie) != 0)
+		err(EX_OSERR, "Existing table check failed");
+
+	if (xi.limit != xie.limit ||
+		xi.type != xie.type ||
+		xi.tflags != xie.tflags ||
+		xi.vmask != xie.vmask ||
+		(xi.algoname[0] != '\0' && strcmp(xi.algoname, xie.algoname) != 0) ||
+		xi.flags != xie.flags)
+		err(EX_OSERR, "Existing table is incompatible with created one");
+
+	/* Flush existing table if instructed so */
+	if (flush != 0)
+		if (table_flush(oh) != 0)
+			err(EX_OSERR, "Table flush on creation failed");
 }
 
 /*